Lake Saginaw
Coordinates: 43°55′N 83°35′W / 43.917°N 83.583°W
Lake Saginaw occupied the basin of Saginaw Bay. There were two periods when it was an independent lake, not associated with a larger body of water in the Huron basin. The first Lake Saginaw was a contemporary of the last stages of Lake Maumee. When the ice border opened allowing these two lakes to become one, it entered the period of Lake Arkona. Then, the ice advanced, closing the link forming the second Lake Saginaw. This was during the time of Lake Whittlesey. When the ice margin retreated northward for the last time, it became the western by of Lake Wayne and then of Lake Warren and Lake Lundy. During its periods as an independent lake, its outlet was west through Grand River channel.
Lake Saginaw began after the building of the Flint moraine and the creation of the Imlay channel (from Flint to Maple Rapids) from glacial runoff. When the ice sheet had retreated into the Saginaw basin, exposing land, water began to accumulate and the First Lake Saginaw was formed.
The outlet of the lake was through Grand River to Lake Chicago, which as served the run-off from the glacier. Well-defined beaches surround the outlet at an altitude 700 feet (210 m) above sea level, To the north and west, they are higher because of isostatic rebound once the glaciers weight had been removed. The bed of the lake is nearly equally divided between a sandy and a clayey soil. Sand due to lake waves and currents is restricted to the border of the lake, while glacial outwash may be present where there was a considerable depth of water,
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